> ## Documentation Index
> Fetch the complete documentation index at: https://docs.crossmint.com/llms.txt
> Use this file to discover all available pages before exploring further.

# OfframpMessage

> Swift Structure

**Structure**

The wallet ownership proof that the offramp asks the payer to sign: a Crossmint sign-in challenge for `payerAddress`.

```swift theme={null}
struct OfframpMessage
```

## Instance Properties

| Property | Type | Description |
| - | - | - |
| `chain` | `String` | The chain of the wallet, for example `base-sepolia` or `solana`. |
| `message` | `String` | The text to sign. |
| `payerAddress` | `String` | The wallet that must sign the message. |